Tube to tube sheet welding for fabrication of vertical boiling reactor with reduced tube pitch

Abstract

Reduced tube pitch within a shell-and-tube heat exchange reactor such as, for example, an EO reactor, is provided by utilizing a welding material that has a high tensile (i.e., a tensile strength of greater than 600 MPa). Reduced tube pitch allows for more elongated tubes (the tubes are filled with a catalyst) to be present in a reactor, and thus a smaller reactor can be manufactured. Notably, the use of a high tensile strength welding material allows the implementation of a small welding groove located between a beveled sidewall of a beveled upper portion of an opening provided in a tube sheet overlay material (that is located atop a tube sheet) and an outermost sidewall of the elongated tube passing through the opening in the tube sheet overlay material.

What is claimed is: 
     
       1. A shell-and-tube heat exchange reactor comprising:
 an inlet tube sheet having a plurality of first openings and located at an inlet end of the reactor; 
 an outlet tube sheet having a plurality of second openings and located at an outlet end of the reactor; 
 a plurality of elongated tubes located between the inlet tube sheet and the outlet tube sheet and passing through the plurality of first and second openings; 
 a tube sheet overlay material located atop each of the inlet tube sheet and the outlet tube sheet, wherein the tube sheet overlay material contains a plurality of third openings configured to allow the plurality of elongated tubes to pass there through, each third opening of the plurality third openings comprises a beveled upper portion having a welding groove located between a beveled sidewall of the beveled upper portion of the third opening and an outermost sidewall of the elongated tube passing through the third opening, wherein the beveled upper portion of the third opening of the tube sheet overlay material has a V-bevel shape, a groove angle from about 30° to about 150°, and a bevel angle from about 15° to about 75°; and 
 a welding material located inside the welding groove and affixed to the outermost sidewall of the elongated tube passing through the third opening, wherein the welding material located inside the welding groove has a tensile strength of greater than 600 MPa. 
 
     
     
       2. The shell-and-tube heat exchange reactor of  claim 1 , wherein the welding groove has a total area from about 1.125 mm 2  to about 10.125 mm 2 , and a length from about 1.5 mm to about 4.5 mm. 
     
     
       3. The shell-and-tube heat exchange reactor of  claim 1 , wherein the tube sheet overlay material has a tensile strength from greater than 600 MPa to about 950 MPa. 
     
     
       4. The shell-and-tube heat exchange reactor of  claim 1 , wherein the tensile strength of the welding material located inside the welding groove is from greater than 600 MPa to about 950 MPa. 
     
     
       5. The shell-and-tube heat exchange reactor of  claim 1 , wherein the welding material located inside the welding groove is composed of a chromium-nickel (Cr—Ni) based alloy. 
     
     
       6. The shell-and-tube heat exchange reactor of  claim 1 , wherein a pitch between each neighboring elongated tube affixed to the tube sheet overlay material is from about 27 mm to about 80 mm. 
     
     
       7. The shell-and-tube heat exchange reactor of  claim 1 , wherein the third opening of the tube sheet overlay material further comprises a non-beveled lower portion in communication with the beveled upper portion. 
     
     
       8. The shell-and-tube heat exchange reactor of  claim 1 , further comprising a fillet welding material located on the welding material present in the welding groove and contacting another portion of the outermost sidewall of the elongated tube. 
     
     
       9. The shell-and-tube heat exchange reactor of  claim 1 , wherein the shell-and-tube heat exchange reactor is an ethylene oxide (EO) reactor. 
     
     
       10. The shell-and-tube heat exchange reactor of  claim 9 , wherein the EO reactor further comprises an inlet line for introducing a feed gas comprising 1% to 40% ethylene and 3% to 12% oxygen into the EO reactor. 
     
     
       11. The shell-and-tube heat exchange reactor of  claim 10 , wherein the EO reactor is configured to operate at a gas hourly space velocity of 1500 to 10,000 h −1 , a reactor inlet pressure of 1 MPa to 3 MPa, a coolant temperature of 180° C. to 315° C., an oxygen conversion level of 10-60%, and an EO production rate (work rate) of 100-350 kg EO/m 3  catalyst/hr and a change in ethylene oxide concentration, ΔEO, of from about 1.5% to about 4.5%. 
     
     
       12. The shell-and-tube heat exchange reactor of  claim 9 , wherein each elongated tube is filled with a silver-based epoxidation catalyst. 
     
     
       13. The shell-and-tube heat exchange reactor of  claim 12 , wherein the silver-based epoxidation catalyst comprises an alumina support, a catalytically effective amount of silver or a silver-containing compound, and a promoting amount of one or more promoters. 
     
     
       14. The shell-and-tube heat exchange reactor of  claim 13 , wherein the one or more promoters comprises at least a rhenium promoter. 
     
     
       15. A shell-and-tube heat exchange reactor comprising:
 an inlet tube sheet having a plurality of first openings and located at an inlet end of the reactor; 
 an outlet tube sheet having a plurality of second openings and located at an outlet end of the reactor; 
 a plurality of elongated tubes located between the inlet tube sheet and the outlet tube sheet and passing through the plurality of first and second openings; 
 a tube sheet overlay material located atop both the inlet tube sheet and the outlet tube sheet, wherein the tube sheet overlay material contains a plurality of third openings configured to allow the plurality of elongated tubes to pass there through, each third opening of the plurality third openings comprises a beveled upper portion having a welding groove having a total area of from about 1.125 mm 2  to about 10.125 mm 2  located between a beveled sidewall of the beveled upper portion of the third opening and an outermost sidewall of the elongated tube passing through the third opening, wherein the beveled upper portion of the third opening of the tube sheet overlay material has a V-bevel shape, a groove angle from about 30° to about 150°, and a bevel angle from about 15° to about 75°; and 
 a welding material located inside the welding groove and affixed to the outermost sidewall of the elongated tube passing through the third opening. 
 
     
     
       16. An ethylene oxide (EO) reactor comprising:
 an inlet tube sheet having a plurality of first openings and located at an inlet end of the EO reactor; 
 an outlet tube sheet having a plurality of second openings and located at an outlet end of the EO reactor; 
 a plurality of elongated tubes located between the inlet tube sheet and the outlet tube sheet and passing through the plurality of first and second openings; 
 a tube sheet overlay material located atop both the inlet tube sheet and the outlet tube sheet, wherein the tube sheet overlay material contains a plurality of third openings configured to allow the plurality of elongated tubes to pass there through, each third opening of the plurality third openings comprises a beveled upper portion having a welding groove located between a beveled sidewall of the beveled upper portion of the third opening and an outermost sidewall of the elongated tube passing through the third opening, wherein the beveled upper portion of the third opening of the tube sheet overlay material has a V-bevel shape, a groove angle from about 30° to about 150°, and a bevel angle from about 15° to about 75°; 
 a welding material located inside the welding groove and affixed to the outermost sidewall of the elongated tube passing through the third opening, wherein the welding material located inside the welding groove has a tensile strength of greater than 600 MPa; and 
 an inlet line for introducing a feed gas comprising 1% to 40% ethylene and 3% to 12% oxygen into the EO reactor, wherein the EO reactor is configured to operate at a gas hourly space velocity of 1500 to 10,000 h −1 , a reactor inlet pressure of 1 MPa to 3 MPa, a coolant temperature of 180° C. to 315° C., an oxygen conversion level of 10-60%, and an EO production rate (work rate) of 100-350 kg EO/m 3  catalyst/hr and a change in ethylene oxide concentration, ΔEO, of from about 1.5% to about 4.5%, and wherein each elongated tube is filled with a silver-based epoxidation catalyst comprising an alumina support, a catalytically effective amount of silver or a silver-containing compound, and a promoting amount of one or more promoters. 
 
     
     
       17. The EO reactor of  claim 16 , wherein the welding groove has a total area from about 1.125 mm 2  to about 10.125 mm 2 , and a length from about 1.5 mm to about 4.5 mm. 
     
     
       18. The EO reactor of  claim 16 , wherein the tube sheet overlay material has a tensile strength from greater than 600 MPa to about 950 MPa. 
     
     
       19. The EO reactor of  claim 16 , wherein the tensile strength of the welding material located inside the welding groove is from greater than 600 MPa to about 950 MPa. 
     
     
       20. The EO reactor of  claim 16 , wherein the welding material located inside the welding groove is composed of a chromium-nickel (Cr—Ni) based alloy. 
     
     
       21. The EO of  claim 16 , wherein a pitch between each neighboring elongated tube affixed to the tube sheet overlay material is from about 27 mm to about 80 mm.